OF THE BLOOD. 235 



concave glass with a little water, and the rays of the sun being 

 made to pass through it, the heart may be seen to beat, and 

 the transparent blood or sanies found to have a few vesicles, 

 which appear to move one after the other ; being made visible, 

 though transparent, by the light passing in such a manner as 

 to be refracted by them. 



Since so small an animal as this has these curious vesicles 

 equally as the larger and more perfect animals, is is not pro- 

 bable that they are diffused through the whole animal creation? 

 And what is found so generally amongst animals must be of 

 great use in their economy (cxvin). 



As these curious vesicles therefore are so universally found 



(cxviu.) The use of the corpuscles is now generally included in that 

 of primary isolated cells. In Note cxxn, p. 254, I have shown how the 

 red corpuscles differ in chemical properties from perfect and immature 

 pale cells. Dr. Barry a concludes that the tissues generally are formed 

 out of the blood-corpuscles, I think without sufficient proof. They 

 have been regarded as the carriers of oxygen ; and if, as Dr. Simon b 

 observes, the greater part of the carbon 'exhaled from the lungs in the 

 form of carbonic acid arises from the red corpuscles, the production of 

 animal heat may be connected with, this consumption by them of 

 oxygen. Henle, c Wagner/ Mr. Wharton Jones, 6 and Mr. Newport, 

 consider the red corpuscles as floating glandular cells, their especial 

 office being, according to Mr. Jones, to convert albumen into fibrin : see 

 Notes i and xvm. Mr. Newport's views are mentioned in Note xci. Dr. 

 Simon's observations f support Mr. Jones's conclusion. Dr. Carpenter 5 

 objects to it, and believes that the pale corpuscles elaborate the fibrin. 

 Certain it is, that fibrin is formed without the immediate agency of the 

 red corpuscles, and in connexion with a great number of colourless 

 ones, in the lymphatic and lacteal vessels of Mammalia and in the blood 

 of Invertebrata. But to both the opinions of Mr. Jones and Dr. Carpenter 

 a simple and heavy objection is the fact, mentioned in Note xvui, 

 that fibrin and its fibrils may be produced, merely by mixing together 

 certain varieties of serum, in which, before mixing, no fibrinous par- 

 ticles can be discerned with the aid of the microscope. As to the 

 opinion that fibrin is formed of the central part of the red corpuscles, 

 Dr. Copland 11 adopts the hypothesis of Sir Everard Home, with the re- 

 finement that the supposed separation of the envelope proceeds from the 



a Phil. Trans. 1840, p. 601 ; and 1841, f Animal Chemistry, tr. for the Sydenham 



p. 217. Society, i, 157, 219. 



b Animal Chemistry, tr. by Dr. Day, for s Brit, and For. Med. Rev. xv, 272-73; 



the Sydenham Society, i, 220. and xviii, 569. 



c Anatomie Generale, tr. par Jourdan, h App. to tr. of Richerand's Physiology, 



torn, i, p. 493. p. 638, 4th ed. 8vo, Lond. 1824; 



d Physiol. tr. by Dr. Willis, pp. 448-49. and Dictionary of Practical Medicine, 



p Brit, and For. Med. Rev. xiv, 597 ; and i, 167, 8vo, Lond. 1844. 



xviii, 260-1, 263. 



